1. Field of Invention
This invention is directed to organizing image data into regions having similar color characteristics.
2. Related Art
Documents scanned at high resolutions typically require very large amounts of storage space. Furthermore, a large volume of image data requires substantially more time and bandwidth to manipulate, such as transferring over a local or wide area network, over an intranet, an extranet or the Internet, or other distributed networks.
Documents, upon being scanned using a scanner or the like, are typically defined using an RGB color space, i.e., in raw RGB format. However, rather than being stored in this raw scanned RGB format, the document image data is typically subjected to some form of data compression to reduce its volume, thus avoiding the high costs of storing such scanned RGB document image data.
Lossless run-length compression schemes, such as Lempel-Ziv (LZ) or Lempel-Ziv-Welch (LZW), do not perform particularly well on scanned image data or, in general, image data having smoothly varying low-spatial frequencies such as gradients and/or natural pictorial data, while lossy methods such as JPEG, work fairly well on smoothly varying continuous tone image data. However, lossy methods generally do not work particularly well on binary text and/or line art image data, or, in general, on any high spatial frequency image data containing sharp edges or color transitions, for example.